In producing petroleum and other useful fluids from production walls, it is generally known to provide a submergible pumping system for raising the fluids collected in a well. Production fluids enter a wellbore via perforations formed in a well casing adjacent a production formation. Fluids contained in the formation collect in the wellbore and may be raised by the submergible pumping system to a collection point above the earth's surface.
In a conventional bottom intake electric submergible pumping system, the system includes several components, such as a submergible electrical motor that supplies energy to a submergible pump. The system may further include a motor protector for isolating the motor from well fluids. A motor connector may also be used to provide a connection between the electrical motor and an electrical power supply. These and other components may be combined in the overall submergible pumping system.
The downhole environment where many submergible pumping systems are used is relatively harsh, subjecting the systems to high temperatures, corrosion, and wear caused by sand and grit suspended in the production fluid. Many areas of submergible pumping systems require reliable seals, which protect against the harsh environment. For example, motor protector seals are critical for preventing contamination of the motor oil with the well fluid.
Conventional seal faces are fabricated through molding and/or sintering processes, but these processes are relatively expensive and are often unworkable for intricate and/or large bearing surfaces. Attempts have been made to coat components at bearing surfaces. For example, thrust bearings have been produced in which the thrust bearing pads have a layer of PEEK material molded over the bearing surface of the pad. Most recently, carbon fiber reinforced PEEK rings have been fabricated for use as wear rings. Although the molding and sintering processes are successful for some components, the processes are costly and not conducive to coating complex surface areas such as inner curvatures.
PEEK coated seal surfaces would be advantageous in that they resist wear and corrosion, work in high temperature environments, and provide a low friction and non-rigid sealing surface for both rotational and stationary applications. It would also be advantageous to directly apply PEEK composite to a seal surface to provide greater flexibility in selecting the thickness, size, intricacy, and location of the seal surface.